1. Field of the Invention
The present invention relates to a circuit board case adapted for mounting to a vehicle, which includes a case for housing a circuit board and a cover for covering the case.
2. Description of the Related Art
In order to detect a specific gas component in the exhaust gas of an internal combustion engine e.g., of an automobile, a gas sensor is widely used. The gas sensor is connected to a circuit board which receives a sensor output signal and controls the gas sensor. Such a circuit board is housed in a case for the purposes of waterproofing, dustproofing, and the like. Further, in order to protect the case from flying gravel, and the like, flung upwards during driving, a circuit board case is configured by covering the case with a cover. The circuit board case covered with the cover is mounted under a floor of the vehicle (see, for example, JP-A-2006-341668).
As shown in FIG. 10, in a general circuit board case, a case 100 is held in a cover 500 by allowing latch claws 110 provided on side surfaces of the case 100 to engage respective engagement holes 510 formed on the side surfaces of the cover 500. The cover 500 is then secured to a frame, or the like, of a vehicle with bolts.
In the case of the above-described circuit board case, the cover 500 is secured to the vehicle with bolts. However, the case 100 is merely held at the side surfaces thereof to the cover 500 by way of the latch claws 110. Therefore, when a large physical impact is inflicted on a front wall of the cover 500 (a surface of the cover 500 opposite the surface of the cover 500 fixed to the vehicle), portions of the cover 500 which face the side surfaces of the case 100 open outward, which may cause the case 100 to fall out of the cover 500.